This application claims priority to a Taiwan application No. 098123242 filed on Jul. 9, 2009.
1. Field of the Invention
The present invention generally relates to an electronic device and more particularly to a display panel.
2. Description of Prior Art
FIG. 1A is a schematic top view of a conventional display panel. FIG. 1B is a schematic top view of one of the pixel unit areas of the display panel shown in FIG. 1A. FIG. 1C is a cross-sectional view of the display panel of FIG. 1A taken along line A-A. FIG. 1D is a cross-sectional view of the pixel unit area of FIG. 1B taken along line B-B. It should be pointed out that for the convenience of illustration, some elements of the display panel are omitted in FIG. 1A and the pixel electrode in FIG. 1B is represented by a broken line. Referring to FIGS. 1A, 1B, 1C and 1D, a conventional electrophoretic display panel 100 includes a first substrate 110, an electrophoresis layer 120, a second substrate 130 and a water-proofing frame 140. The first substrate 110 has a view area V1 and includes a first base 111, a circuit layer 112, a passivation layer 113, a bibulous planarization layer 114 and a pixel-electrode layer 115.
The circuit layer 112 is disposed on the first base 111 and includes a plurality of data lines 112a, a plurality of scan lines 112b and a plurality of switching elements 112c. Each of the switching elements 112c is a thin-film transistor (TFT). A plurality of pixel unit areas P1 are separated by the data lines 112a and the scan lines 112b. The pixel unit areas P1 are located in the view area V1. Each of the switching elements 112c is electrically connected to one of the data lines 112a and one of the scan lines 112b. Each of the switching elements 112c is disposed in one of the pixel unit areas P1.
The passivation layer 113 is disposed on the first base 111 and the circuit layer 112. The bibulous planarization layer 114 composed of resin is disposed on the passivation layer 113. The passivation layer 113 and the bibulous planarization layer 114 expose a part of each of the switching elements 112c. The exposed part of each of the switching elements 112c is a drain electrode D1 thereof. The pixel-electrode layer 115 is disposed on the bibulous planarization layer 114 and includes a plurality of pixel electrodes 115a respectively corresponding to the pixel unit areas P1. Each of the pixel electrodes 115a is located in the view area V1 and electrically connected to the exposed part of one of the switching elements 112c. That is, each of the pixel electrodes 115a is electrically connected to the drain electrode D1 of one of the switching elements 112c. 
The electrophoresis layer 120 is disposed on the pixel-electrode layer 115 and corresponds to the view area V1 of the first substrate 110. The second substrate 130 is disposed on the electrophoresis layer 130 and includes a second base 132 and a common-electrode layer 134. The common-electrode layer 134 is disposed between the second base 132 and the electrophoresis layer 120. The water-proofing frame 140 is disposed on the bibulous planarization layer 114 and surrounds the view area V1. The water-proofing frame 140 connects the first substrate 110 and the second substrate 130. The electrophoresis layer 120 is disposed in a space surrounded by the water-proofing frame 140.
However, when the conventional electrophoretic display panel 100 is used in a moist environment, the bibulous planarization layer 114 of which the thickness is low still absorb moisture from the air and then the moisture from outer environment comes into the view area V1 of the first substrate 110 of the electrophoretic display panel 100. Therefore, the switching elements 112c in the view area V1 and the electrophoresis layer 120 corresponding to the view area V1 may be damaged due to the invasion of moisture from the outer environment such that the reliability of the electrophoretic display panel 100 is reduced.